A moderate spatial resolution land surface phenology product at 30 meter-spatial resolution based on harmonized Landsat 8 and Sentinel 2 imagery for North America has been released and is now available to the science community.  The data set was created by the Land Cover and Surface Climate Group at Boston University (www.bu.edu/lcsc), and is designed to support basic research and applied analyses and modeling efforts that require landscape-scale information related sub-seasonal scale variation in ecosystem properties and land surface phenology.  Data are generated annually and are currently available from the Land Processes Distributed Active Archive Center. 

More info: https://lpdaac.usgs.gov/products/mslsp30nav001/

Reference: Bolton, D, K., Gray, J.M, Melaas, E.K., Moon, M., Eklundh, L. and M.A. Friedl (2020). Continental-scale land surface phenology from harmonized Landsat 8 and Sentinel-2 imagery, Remote Sensing of Environment, 240, https://doi.org/10.1016/j.rse.2020.111685.